scholarly journals INFLUENCE OF ENVIRONMENTAL CONDITION ON SULFATE RESISTANCE OF HARDENED CEMENTITIOUS MATERIALS USING ADMIXTURES

2013 ◽  
Vol 67 (1) ◽  
pp. 348-355 ◽  
Author(s):  
Kennosuke SATO ◽  
Tsuyoshi SAITO ◽  
Tatsuhiko SAEKI ◽  
Michio KIKUCHI
Keyword(s):  
Cementitious Materials ◽  
Environmental Condition ◽  
Sulfate Resistance

scholarly journals Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4206 ◽  
Author(s):  
Carlos H. Aramburo ◽  
César Pedrajas ◽  
Rafael Talero
Keyword(s):  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Chemical Effect ◽  
Portland Cements ◽  
Calcined Clay ◽  
Blended Cements ◽  
Sulfate Resistance ◽  
Type Iv ◽  
Mechanical Strengths ◽  
Mineralogical Compositions

Calcined clay has become the supplementary cementitious materials with the greatest potential to reduce the clinker/cement. In this research, the mechanical strengths and sulphate resistance of blended cements with a high content of calcined clay as a pozzolanic addition were evaluated to demonstrate that these cements could be designed as CEM (cement) type IV/A-SR and IV/B-SR cements by the current European standard UNE-EN 197-1: 2011. The blended cements were prepared by two Portland cements (P1 and PY6) with different mineralogical compositions and a calcined clay. The level of replacement was greater than 40% by weight. The results obtained confirm the decrease in the mechanical strengths and the increase in the sulfate resistance of the two Portland cements when they are replaced by calcined clay at a level of replacement greater than 40%. These results are a consequence of the chemical effect from the pozzolanic activity of the calcined clay. Therefore, there is an important decrease in portlandite levels of paste liquid phase that causes the increase in sulfate resistance and the decrease of the mechanical strengths.

scholarly journals Performance Testing of Hydraulic Cements: Measuring Sulfate Resistance

2018 ◽  
Vol 123 ◽  
Author(s):  
Chiara F. Ferraris ◽  
Paul E. Stutzman ◽  
Max Peltz
Keyword(s):  
Test Procedure ◽  
Performance Testing ◽  
Rapid Test ◽  
Sulfate Solution ◽  
Cementitious Materials ◽  
Decision Time ◽  
Test Method ◽  
Test Duration ◽  
Test Protocol ◽  
Sulfate Resistance

The sulfate resistance of cements used in the construction industry is traditionally assessed by measuring the expansion of a prism of 280 mm (11inch) length and 25 mm (1 inch) square cross section immersed in a sodium sulfate solution for at least one year. The duration of the experiment limits this test from being used as a performance-based determination of innovative mixtures of cementitious materials. In response to the need for a more rapid test protocol, the National Institute of Standards and Technology (NIST) has developed a new test method that measures the expansion of smaller bars (10 mm x 10 mm x 60 mm) made with neat cement paste. With these bars, similar expansion is achieved in less than 3 months, reducing the test duration by a factor of at least 4. This accelerated test method provides more rapid results consistent with the traditional test procedure, allowing for a shorter decision time and the screening of more materials.

scholarly journals Sulfate Resistance in Cements Bearing Bottom Ash from Biomass-Fired Electric Power Plants

2020 ◽  
Vol 10 (24) ◽  
pp. 8982
Author(s):  
José M. Medina ◽  
María Isabel Sánchez de Rojas ◽  
Isabel F. Sáez del Bosque ◽  
Moisés Frías ◽  
César Medina
Keyword(s):  
Electric Power ◽  
Power Plants ◽  
A Priori ◽  
Bottom Ash ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Blended Cements ◽  
Sulfate Resistance ◽  
Electric Power Plants ◽  
Before And After

To address some of the gaps in the present understanding of the behavior of new supplementary cementitious materials such as bottom ash (BA) from biomass-fired electric power plants in cement manufacture, this study explored the effect of this promising material on the sulfate resistance of the end product. Cement paste prepared with 10% or 20% (previously characterized for mineralogy and chemical composition) BA was Köch–Steinegger tested for sulfate resistance. The hydration products, in turn, were analyzed before and after soaking the reference and experimental cements in sodium sulfate to determine whether the use of the addition hastened microstructural, mineralogical, or morphological decay in the material. The 56 days findings showed that the presence of BA raised binder resistance to sulfate attack. Köch–Steinegger corrosion indices of 1.29 and 1.27 for blended cements OPC + 10 BA and OPC + 20 BA, respectively, were higher than the 1.26 recorded for ordinary Portland cement (OPC). In addition, weight gain was 20.5% and volume expansion was 28.5% lower in the new materials compared to OPC. The products resulting from the external sulfate-cement interaction, gypsum and ettringite, were deposited primarily in the pores present in the pastes. The conclusion drawn is that binders bearing 10% or 20% BA are, a priori, apt for use in the design and construction of cement-based elements exposed to sulfate-laden environments.

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